Spiral welded steel pipes refer to steel pipes with seams on the surface that are welded by steel strips or steel plates that are bent into round or square shapes. According to different welding methods, it can be divided into arc welded pipe, high frequency or low frequency resistance welded pipe, gas welded pipe, furnace welded pipe, Bondi pipe, etc. According to the weld shape, it can be divided into straight seam welded pipe and spiral welded pipe. Electric welded steel pipes are used in oil drilling and machinery manufacturing. Furnace welded pipes can be used as water gas pipes, large-diameter longitudinally welded pipes are used for high-pressure oil and gas transportation, etc.; spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. Welded steel pipes have lower cost and higher production efficiency than seamless steel pipes.
Longitudinal welded pipe production process is simple, high production efficiency, low cost, and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. A narrower blank can be used to produce welded pipes with larger pipe diameters, and a billet with the same width can be used to produce welded pipes with different pipe diameters. However, compared with the straight seam pipe of the same length, the weld length is increased by 30-100%, and the production speed is lower. Therefore, most of the smaller diameter welded pipes adopt straight seam welding, and the large diameter welded pipes mostly adopt spiral welding.
